5.7.2 Selections

All choices have a selection. This is a state representing the items currently selected. The selection is represented as a vector of offsets into the list of the choice's items, unless it is a single-selection choice, in which case it is just represented as an offset.

The initial selection is controlled with the initarg
:selection. The accessor
choice-selection
is provided.

Generally, it is easier to refer to the selection in terms of the items selected, rather than by offsets, so the CAPI provides the notion of a
selected item
and the
selected items
. The first of these is the selected item in a single-selection choice. The second is a list of the selected items in any choice.

The accessors
choice-selected-item
and
choice-selected-items
and the initargs
:selected-item and
:selected-items provide access to these conceptual slots.